Caching

Wrap any provider with CachedProvider to add in-memory TTL-based caching. This is recommended for all network-backed providers (HTTP, DynamoDB, PostgreSQL).

CachedProvider implements both BucketRegistry and CredentialRegistry when the inner provider does. Credential and role lookups are cached; bucket resolution and listing are delegated directly (since they involve identity-aware authorization).

Usage

use multistore_server::cached::CachedProvider;
use std::time::Duration;

let base = HttpProvider::new("https://config-api.internal".into(), None);
let provider = CachedProvider::new(base, Duration::from_secs(300));

The first call hits the underlying provider; subsequent calls within the TTL return cached data.

Cache Behavior

• Thread-safe: Uses RwLock internally, safe for concurrent access
• Lazy eviction: Expired entries are evicted on access, not proactively
• Per-entity caching: Each role and credential is cached independently
• BucketRegistry pass-through: get_bucket and list_buckets are always delegated to the inner provider (authorization must not be cached)

Manual Invalidation

// Invalidate everything
provider.invalidate_all();

// Invalidate a specific bucket
provider.invalidate_bucket("my-bucket");

Recommended TTLs

Provider	Suggested TTL	Rationale
HTTP API	60–300s	Balance between freshness and API load
DynamoDB	60–300s	Reduce read capacity costs
PostgreSQL	30–120s	Reduce query load

The server example binary uses a 60-second TTL by default when wrapping the static file provider.